The invention relates to a method for fabricating a toothing at a three-dimensional body produced by forming and fine blanking, especially an attachment for car seat components or the like produced out of a flat strip, wherein the flat strip is formed by forming and fine blanking in a tool into a pot-shaped body with inner forms in a base of the body, including impressions and/or projections and/or indentations and/or recesses and/or sinks and/or holes and/or pivots and a substantially evenly curved edge. Subsequently, a toothing radially extending to the inner side of the body is fabricated into the edge.
The invention further relates to a device for the fabrication of a toothing at a three-dimensional pot-shaped body produced by forming and fine blanking, especially a hinge attachment for car seat components or the like, with a tool for forming teeth into a substantially evenly curved edge of a pot-shaped body having inner forms in a base thereof, such as, for example, impressions and/or projections and/or indentations and/or recesses and/or sinks and/or holes and/or pivots, wherein the teeth of the toothing radially extend to the inner side of the pot-shaped body, in which the three-dimensional body is fixed between a base plate and a pressure pad.
Conventionally, seat adjustment components, for example, fixed and swivelling hinge parts of hinge attachments, are produced by forming, fine blanking or stamping, with the necessary high dimensional accuracy for their final intended use. These hinge parts for transmitting rotational movements have inner or outer toothings, which are formed as projections in one piece with the respective hinge part (DE 32 44 399 C2, DE 28 34 492 C2, DE 32 27 222 C1).
It is common to produce toothings at hinge attachments by fine blanking (DE 32 44 399 C2, DE 198 01 431 A1). These known hinge attachments all consist of disk-shaped attachment parts. But when the body hinge attachments have a dynamically balanced, i.e., three-dimensional, form, toothings heretofore could not be economically produced by common fine blanking, because the burr developing during fine blanking cannot be removed, even by a downstream second process step due to the three-dimensional transitions in the region of the fine blanking surface. Consequently, inner toothings at three-dimensional hinge attachments are produced by cold forming (see, for example, DE 197 50 184 A1). This, however, is connected with the disadvantage of reduced dimensional accuracy of the teeth, because the tips of the teeth are always rounded. Furthermore, cold forming is associated with the disadvantage that an additional heat treatment, for example, interstage annealing of the cold formed toothing, becomes necessary, which in turn leads to a loss of time and higher production costs.
In view of the current state of the art, it is an object of the invention to provide a method and a device for the fabrication of a toothing at a pot-shaped body produced by forming and fine blanking, in a way that the fine blanking of toothings is economically applicable also in case of dynamically balanced three-dimensional bodies, such as, hinge attachments with simultaneously increasing dimensional accuracy of the toothing, wherein the process safety is increased because of the cessation of the heat treatment and the tool can be designed more compactly.